Daughter of the legendary Henry Fonda, she was born in 1937, and followed her father into acting. After achieving a great deal of notability (as well as a large male fanbase) for her roles in films like Cat Ballou, Barefoot in the Park, Barbarella and Klute, for which she won an Oscar, she pulled the PR gaffe to end all PR gaffes.
Fonda, like many of her generation, protested The Vietnam War. However, going to Hanoi in 1972 and publicly supporting North Vietnam (including allowing herself to be photographed sitting on an AA gun) was a step too far for the US public, gaining her the nickname "Hanoi Jane". She later apologised (for the photo, not her trip in general), but many still see her as a traitor. It doesn't help that she also made broadcasts on Radio Hanoi that (whether intended to or not) were exploited by the North Vietnamese for propaganda purposes, and helped in using American POWs as props at a staged "press Conference" to "prove" to the world that the POWs were not being mistreated and were merely opportunistic liars, and years after the war continued to denigrate the men who were held by Vietnam as "liars" when they came forward to describe the abuse doled out to them. (However, the second part of the story, that Fonda deliberately betrayed POWs who asked her to smuggle messages back home to the guards appears to be made up.)
Her career waned in the mid-'70s, but at the end of the decade, she had a successful comeback, winning her second Oscar for the Vietnam War film Coming Home. In 1980, she had one of her greatest commercial successes with Nine to Five. In 1981, she appeared as Henry Fonda's daughter in On Golden Pond.
In The Eighties, she released a series of very successful workout videos, popularizing aerobics. In 1990 she retired from filmmaking, but returned in 2005 with Monster-in-Law. In 2009 she appeared on Broadway again for the first time in 46 years, in 33 Variations, a play about a scholar of the work of Ludwig Van Beethoven.
She was politically active in several causes; she supported civil rights, the feminist movement, and Native American rights, and opposed the Iraq War.
She won two Oscars and was nominated for five more.